Flexible and steerable elongate instruments with shape control and support elements

ABSTRACT

An instrument having a flexible and elongated body includes at least a lumen and a flex member disposed within the lumen. The flex member may be capable of providing steering control to a first portion of the elongate body while providing load bearing support to a second portion of the elongate body. A pull wire may be disposed within the flex member, and at least a distal portion of the pull wire may be coupled to the elongate body and a proximal portion of the pull wire may be operatively coupled to a control unit. The control unit may be coupled to a proximal portion of the elongate body. In addition, a control member may be operatively coupled to the control unit such that a distal portion of the control member may be positioned near a proximal portion of the flex member. The control member may be configured to support the flex member and control the movement or displacement of the flex member. Furthermore, the flex member may be configured to selectively decouple articulation or steering forces of a first portion of the elongate body away from a second portion of the elongate body; thereby, preventing compression of the second portion of the elongate body while maintaining elasticity or flexibility of the second portion of the elongate body.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/432,683, filed Apr. 29, 2009, entitled “FLEXIBLE AND STEERABLEELONGATE INSTRUMENTS WITH SHAPE CONTROL AND SUPPORT ELEMENTS,” theentirety of which is herein incorporated by reference.

FIELD OF INVENTION

The present invention relates generally to robotically controlledsystems, such as robotic or telerobotic surgical systems, and moreparticularly to flexible and steerable elongate instruments or catheterswith adjustable or changeable shape and articulation control forperforming minimally invasive surgical operations.

BACKGROUND

Standard surgical procedures or open surgeries typically involve using ascalpel to create an opening of sufficient size to allow a surgical teamto gain access to an area in the body of a patient for the surgical teamto diagnose and treat one or more target sites. When possible, minimallyinvasive surgical procedures may be used instead of standard surgicalprocedures to minimize physical trauma to the patient and reducerecovery time for the patient to recuperate from the surgicalprocedures. However, minimally invasive surgical procedures typicallyrequire using extension tools to approach and address the target site,and the typical extension tools may be difficult to use, manipulate, andcontrol. Consequently, only a limited number of surgeons may have thenecessary skills to proficiently manipulate and control the extensiontools for performing complex minimally invasive surgical procedures. Assuch, standard surgical procedures or open surgery might be chosen forthe patient even though minimally invasive, surgical procedures may bemore effective and beneficial for treating the patient.

Accordingly, there is a need to develop extension tools that are easy touse, manipulate, and control, especially for performing complexminimally invasive surgical procedures.

SUMMARY

In accordance with one embodiment, a steerable elongate instrument hasan elongate body with a first lumen and a second lumen within theelongate body. A flex member may be disposed within the second lumen,and a pull wire may be disposed within the flex member. A distal portionof the pull wire may be coupled to a distal portion of the elongate bodyand a proximal portion of the pull wire may be operatively coupled to acontrol unit. The control unit may be coupled to a proximal portion ofthe elongate body.

According to another embodiment, a steerable elongate instrument has anelongate body with a primary lumen, a plurality of secondary lumenswithin the elongate body, and a plurality of flex members wherein eachone of the flex members may be disposed within each one of the pluralityof secondary lumens. The steerable elongate instrument may furtherinclude a plurality of pull wires wherein each of the pull wires may berespectively disposed within one of the flex members, and the distalportions of the pull wires may be coupled to different locations orportions of the elongate body and proximal portions of the pull wiresmay be operatively coupled to a control unit. The control unit may becoupled to a proximal portion of the elongate body.

According to another embodiment, a steerable elongated instrument has anelongate body with a plurality of lumens within the elongate body. Thesteerable elongate instrument may also include a plurality of flexmembers, and each of the flex members may be respectively disposedwithin each one of the lumens. The steerable elongate instrument mayfurther include a plurality of pull wires, and each of the pull wiresmay be respectively disposed within one of the flex members such thatdistal portions of the pull wires may be coupled to different locationsor portions of the elongate body and proximal portions of the pull wiresmay be operatively coupled to a control unit. The control unit may becoupled to a proximal portion of the elongate body.

According to another embodiment, a steerable elongate instrument has anelongate body with a first lumen and a second lumen within the elongatebody. A flex member may be disposed within the second lumen, and theflex member may be configured to provide steering control to a firstportion of the elongate body and load bearing support to a secondportion of the elongate body. A pull wire may be disposed within theflex member wherein a distal portion of the pull wire may be coupled toa distal portion of the elongate and a proximal portion of the pull wiremay be operatively coupled to a control unit. The control unit may becoupled to a proximal portion of the elongate body and the control unitmay be configured to operate the pull wire for applying forces toarticulate or steer the first portion of the elongate body.

According to another embodiment, a steerable elongate instrument has anelongate body with a primary lumen and a plurality of secondary lumenswithin the elongate body. The elongate instrument may also include aplurality of flex members such that each of the flex members may berespectively disposed within each of the plurality of secondary lumens.The flex members may be configured to provide steering control todifferent distal portions of the elongate body and load bearing supportto different proximal portions of the elongate body. The elongateinstrument further includes a plurality of pull wires and each of thepull wires may be respectively disposed within each of the plurality ofthe flex members. The distal portions of the pull wires may be coupledto different distal locations or portions of the elongate body andproximal portions of the pull wires may be operatively coupled to acontrol unit. The control unit may be coupled to a proximal portion ofthe elongate body, and the control unit may be configured to operate thepull wires for applying forces to articulate or steer the differentdistal locations or portions of the elongate body.

According to another embodiment, a steerable elongate instrument has anelongate body with a plurality of lumens within the elongate body. Theelongate instrument also has a plurality of flex members, and each ofthe flex members may be respectively disposed within each of theplurality of lumens. The flex members may be configured to providesteering control to different distal portions of the elongate body andload bearing support to different proximal portions of the elongatebody. The elongate instrument also includes a plurality of pull wires,and each of the pull wires may be respectively disposed within each ofthe flex members. Distal portion of respective pull wires may be coupledto different distal locations or portions of the elongate body, andproximal portion of respective pull wires may be operatively coupled toa control unit. The control unit may be coupled to a proximal portion ofthe elongate body. The control unit may be configured to operate therespective pull wires for applying forces or loads to articulate orsteer the different distal locations or portions of the elongate body.

According to another embodiment, an instrument has a flexible andelongate body that has at least one lumen. A flex member may be disposedwithin the lumen, and the flex member may be capable of providingsteering control to a first portion of the elongate body while providingload bearing support to a second portion of the elongate body. A pullwire may be disposed within the flex member, and at least a distalportion of the pull wire may coupled to the elongate body and a proximalportion of the pull wire may be operatively coupled to a control unit.The control unit may be coupled to a proximal portion of the elongatebody.

According to another embodiment, an instrument includes a flexible andelongate body that has at least one lumen. A flex member may be disposedwithin the lumen, and the flex member may be capable of providingsteering control to a first portion of the elongate body while providingload bearing support to a second portion of the elongate body. A pullwire may be disposed within the flex member, and at least a distalportion of the pull wire may coupled to the elongate body and a proximalportion of the pull wire may be operatively coupled to a control unit.The control unit may be coupled to a proximal portion of the elongatebody. The flex member may be further configured to selectively decouplearticulation or steering forces of a first portion of the elongate bodyaway from a second portion of the elongate body; thereby, preventingcompression of the second portion of the elongate body while maintainingelasticity or flexibility of the second portion of the elongate body.

According to another embodiment, a method of shape or articulationcontrol of an elongate instrument may be provided. The method mayinclude inserting an elongate instrument into a patient through eitheran incision or orifice, advancing the elongate instrument through apathway inside the patient, manipulating the elongate instrument toconform or match a shape or curvature of the pathway as the elongateinstrument is being advanced through the pathway, and steering orarticulating a distal portion of the elongate instrument around othercurvatures of the pathway.

According to another embodiment, a steerable elongate instrument has anelongate body with a first lumen and a second lumen within the elongatebody, and a flex member may be disposed within the second lumen. A pullwire may be disposed within the flex member, wherein a distal portion ofthe pull wire may be coupled to a distal portion of the elongate bodyand a proximal portion of the pull wire may be operatively coupled to acontrol unit. The control unit may be coupled to a proximal portion ofthe elongate body, and a control member may be operatively coupled tothe control unit wherein a distal portion of the control member may bepositioned near a proximal portion of the flex member.

According to another embodiment, a steerable elongate instrument has anelongate body with a primary lumen and a plurality of secondary lumenswithin the elongate body. The steerable elongate instrument may alsoinclude a plurality of flex members, and each of the plurality of flexmembers may be respectively disposed within each of the secondarylumens. The steerable elongate instrument may further include aplurality of pull wires wherein each of the pull wires may berespectively disposed within each of the flex members, and distalportion of each of the pull wires may be coupled to different locationsor portions of the elongate body and proximal portion of each of thepull wires are operatively coupled to a control unit. The control unitmay be coupled to a proximal portion of the elongate body. A pluralityof control members may be operatively coupled to the control unit suchthat distal portions of the control members may positioned near theproximal portions of the flex members.

According to another embodiment, a steerable elongate instrument has anelongate body with a plurality of lumens within the elongate body and aplurality of flex members. Each of the flex members may be respectivelydisposed within each of the lumens. The steerable elongate instrumentmay also includes a plurality of pull wires, and each of the pull wiresmay be respectively disposed within each of the flex members such thatdistal portion of each of the pull wires may coupled to differentlocations or portions of the elongate body and proximal portion of eachof the pull wires may be operatively coupled to a control unit. Thecontrol unit may be coupled to a proximal portion of the elongate body,and a plurality of control members may be operatively coupled to thecontrol unit wherein distal portions of the control members may bepositioned near the proximal portions of the flex members.

According to another embodiment, a steerable elongate instrument has anelongate body having a first lumen and a second lumen within theelongate body and a flex member disposed within the second lumen. Theflex member may be configured to provide steering control to a firstportion of the elongate body and load bearing support to a secondportion of the elongate body. A pull wire may be disposed within theflex member, and a distal portion of the pull wire may be coupled to adistal location or portion of the elongate body and a proximal portionof the pull wire may be operatively coupled to a control unit. Thecontrol unit may be coupled to a proximal portion of the elongate bodyand the control unit may be configured to operate the pull wire forapplying forces to articulate or steer the first portion of the elongatebody. A control member may be operatively coupled to the control unitwherein a distal portion of the control member may be positioned near aproximal portion of the flex member. The control member may beconfigured to support the flex member and control movement ordisplacement of the flex member.

According to another embodiment, an instrument having a flexible andelongated body includes at least a lumen and a flex member disposedwithin the lumen. The flex member may be configured to provide steeringcontrol to a first portion of the elongate body while providing loadbearing support to a second portion of the elongate body. A pull wiremay be disposed within the flex member, and at least a distal portion ofthe pull wire may be coupled to the elongate body and a proximal portionof the pull wire may be operatively coupled to a control unit. Thecontrol unit may be coupled to a proximal portion of the elongate body.In addition, a control member may be operatively coupled to the controlunit such that a distal portion of the control member may be positionednear a proximal portion of the flex member. The control member may be.configured to support the flex member and control the movement ordisplacement of the flex member. Furthermore, the flex member may beconfigured to selectively decouple articulation or steering forces of afirst portion of the elongate body away from a second portion of theelongate body; thereby, preventing compression of the second portion ofthe elongate body while maintaining elasticity or flexibility of thesecond portion of the elongate body.

According to another embodiment, a steerable elongate instrument has anelongate body with a primary lumen, a plurality of secondary lumenswithin the elongate body, and a plurality of flex members. Each of theplurality of flex members may be disposed within each of the secondarylumens. The flex members may be configured to provide steering controlto different distal portions of the elongate body and load bearingsupport to different proximal portions of the elongate body. Thesteerable elongate instrument may also include a plurality of pull wireswherein each of the pull wires may be disposed within each of the flexmembers. In addition, distal portion of each of the pull wires may becoupled to different distal locations or portions of the elongate bodyand proximal portion of each of the pull wires may be operativelycoupled to a control unit. The control unit may be coupled may becoupled to a proximal portion of the elongate body. Furthermore, aplurality of control members may be operatively coupled to the controlunit wherein distal portions of the control members may be positionednear the proximal portions of the flex members, and the control membersmay be configured to support the flex members and control movement ordisplacement of the flex members.

According to another embodiment, a steerable elongate instrument has anelongate body with a plurality of lumens within the elongate body and aplurality of flex members. Each of the flex members may be disposedwithin each of the lumens, and the flex members may be configured toprovide steering control to different distal portions of the elongatebody and load bearing support to different proximal portions of theelongate body. The steerable elongate instrument may also include aplurality of pull wires. Each of the pull wires may be disposed withineach of the flex members, wherein distal portion of each of the pullwires may be coupled to different distal locations or portions of theelongate body and proximal portion of each of the pull wires may beoperatively coupled to a control unit. The control unit may be coupledto a proximal portion of the elongate body. The steerable instrument mayfurther include a plurality of control members that may be operativelycoupled to the control unit such that distal portions of the controlmembers may be positioned near the proximal portions of the flexmembers. The control members may be configured to support the flexmembers and control movement or displacement of the flex members.

According to another embodiment, a method of shape or articulationcontrol of an elongate instrument may be provided. The method mayinclude inserting an elongate instrument into a patient through eitheran incision or orifice, advancing the elongate instrument through apathway inside the patient, manipulating the elongate instrument toconform or match a shape or curvature of the pathway as the elongateinstrument is being advanced through the pathway, and steering orarticulating a distal portion of the elongate instrument around othercurvatures of the pathway. In addition, the method may further includeadvancing a control member against a proximal portion of a flex memberof the elongate instrument. The method may also include locking theconformed or matched shape or curvature of a proximal portion of theelongate instrument.

According to another embodiment, a method of shape of articulationcontrol of an instrument may be provided. The method may includeinserting an elongate instrument into a patient, wherein the elongateinstrument comprises a distal portion, a mid portion, and a proximalportion. The method may also include advancing the distal and midportions of the elongate instrument through a pathway inside thepatient, manipulating the mid portion of the elongate instrument toconform to a shape or curvatures in the pathway as the elongateinstrument is being advanced through the pathway, and locking the midportion of the elongate instrument such that the mid portion maintainsthe conformed shape or curvatures while the distal portion of theelongate instrument is manipulated to assume a curvature independent ofthe mid portion.

According to another embodiment, a steerable elongate instrument has anelongate body with a first lumen and a second lumen within the elongatebody, a flex member disposed within the second lumen, and a first pullwire disposed within the flex member wherein a distal portion of thefirst pull wire may be coupled to a distal portion of the elongate bodyand a proximal portion of the first pull wire may be operatively coupledto a control unit. The control unit may be coupled to a proximal portionof the elongate body. A second pull wire may be disposed within the flexmember, and a distal portion of the second pull wire may be coupled to adistal portion of the flex member and a proximal portion of the secondpull wire may be operatively coupled to the control unit. Additionally,a control member may be operatively coupled to control unit such that adistal portion of the control member may be positioned near a proximalportion of the flex member.

According to another embodiment, a steerable elongate instrument has anelongate body with a first lumen and a second lumen within the elongatebody, and a flex member disposed within the second lumen. The flexmember may be configured to provide steering control to a first portionof the elongate body and load bearing support to a second portion of theelongate body. The steerable instrument may also include a first pullwire and a second pull wire. A distal portion of the first pull wire maybe coupled to a distal portion of the elongate body and a proximalportion of the first pull wire may be operatively coupled to a controlunit. The control unit may be coupled to a proximal portion of theelongate body, and the control unit may be configured to operate thefirst pull wire for applying forces to articulate or steer the firstportion of the elongate body. In addition, a distal portion of thesecond pull wire may be coupled to a distal portion of the flex memberand a proximal portion of the second pull wire may be operativelycoupled to the control unit. The control unit may be configured tooperate the second pull wire to control displacement of the flex member.The steerable instrument may further include a control member that maybe operatively coupled to the control unit such that a distal portion ofthe control member may be positioned near a proximal portion of the flexmember. The control member may be configured to control displacement ofthe flex member.

According to another embodiment, a method for shape or articulationcontrol may be provided. The method may include inserting an elongateinstrument into a patient through either an incision or orifice,advancing the elongate instrument through a pathway inside the patient,manipulating the elongate instrument to conform or match a shape orcurvature of the pathway as the elongate instrument is being advancedthrough the pathway, controlling the displacement of a flex member alonga length of the elongate instrument, and steering a first portion or asecond portion of the elongate instrument around curvatures of thepathway.

According to another embodiment, a method of shape or articulationcontrol may be provided. The method may include inserting an elongateinstrument into a patient through either an incision or orifice,advancing the elongate instrument through a pathway inside the patient,manipulating the elongate instrument to conform or match a shape orcurvature of the pathway as the elongate instrument is being advancedthrough the pathway, controlling the displacement of a flex member alonga length of the elongate instrument, altering the stiffness of a firstportion of the elongate instrument, changing the radius of curvature ofthe elongate instrument, and steering the first portion or secondportion of the elongate instrument around curvatures of the pathway.

According to another embodiment, an instrument having a flexible andelongated body includes at least two lumens and a flex member disposedwithin one of the lumens. The flex member may be capable of providingsteering control to a first portion of the elongate body while providingload bearing support to a second portion of the elongate body. A pullwire may be disposed within the flex member, and at least a distalportion of the pull wire may be coupled to the elongate body and aproximal portion of the pull wire may be operatively coupled to acontrol unit. The control unit may be coupled to a proximal portion ofthe elongate body. In addition, a control member may be operativelycoupled to the control unit such that a distal portion of the controlmember may be positioned near a proximal portion of the flex member. Thecontrol member may be configured to support the flex member and controlthe movement or displacement of the flex member. Furthermore, the flexmember may be configured to be anchored to the elongate body between thefirst and second portion of the elongate body to selectively decouplearticulation or steering forces of a first portion of the elongate bodyaway from a second portion of the elongate body; thereby, preventingtwist or compression of the second portion of the elongate body whilemaintaining elasticity or flexibility of the second portion of theelongate body.

According to another embodiment, an instrument having a flexible andelongated body includes at least two lumens and a flex member disposedwithin one of the lumens. The flex member may be capable of providingsteering control to a first portion of the elongate body while providingload bearing support to a second portion of the elongate body. A pullwire may be disposed within the flex member, and at least a distalportion of the pull wire may be coupled to the elongate body and aproximal portion of the pull wire may be operatively coupled to acontrol unit. The control unit may be coupled to a proximal portion ofthe elongate body. In addition, a control member may be operativelycoupled to the control unit such that a distal portion of the controlmember may be positioned near a proximal portion of the flex member. Thecontrol member may be configured to support the flex member and controlthe movement or displacement of the flex member. Furthermore, the flexmember may be configured to be anchored to the elongate body between thefirst and second portion of the elongate body to selectively decouplearticulation or steering forces of a first portion of the elongate bodyaway from a second portion of the elongate body; thereby, preventingtwist or compression of the second portion of the elongate body whilemaintaining elasticity or flexibility of the second portion of theelongate body. In addition, the flex member may not be anchored to theelongate body; instead, it may be positioned at various locations of theelongate body to affect or alter the bending stiffness of varioussections or portions of the elongate body. Moreover, by way of aretractable anchor, the flex tube may operate as a structure or devicethat decouples articulation forces from at least a portion of theelongate body, and the flex tube may also operate as a structure ordevice that could affect or alter the bending stiffness to at least aportion of the elongate body.

Other and further features and advantages of embodiments of theinvention will become apparent from the following detailed description,when read in view of the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description, taken in conjunction with accompanying drawings,illustrating by way of examples the principles of the invention. Theobjects and elements in the drawings are not necessarily drawn to scale,proportion, precise orientation or positional relationships; instead,emphasis is focused on illustrating the principles of the invention. Thedrawings illustrate the design and utility of various embodiments of thepresent invention, in which like elements are referred to by likereference symbols or numerals. The drawings, however, depict theembodiments of the invention, and should not be taken as limiting itsscope. With this understanding, the embodiments of the invention will bedescribed and explained with specificity and detail through the use ofthe accompanying drawings in which:

FIG. 1 illustrates one example of a robotic or telerobotic surgicalsystem.

FIG. 2A through FIG. 2D illustrate various embodiments of an instrumentassembly.

FIG. 3A illustrates a cross-sectional view of a flexible and steerableelongate instrument with variable or changeable shape control andsupport elements in accordance with one embodiment.

FIG. 3B illustrates another cross-sectional view (View 1-1) of aflexible and steerable elongate instrument with variable or changeableshape control and support elements in accordance with one embodiment.

FIG. 4A illustrates an elongate instrument with passively controlledflex member in accordance with one embodiment.

FIG. 4B illustrates a passively controlled flex member with a service orbuffer loop in accordance with one embodiment.

FIG. 4C illustrates support tubes or support members sliding along theflex tubes or flex members in accordance with one embodiment.

FIG. 4D illustrates slidable couplings of variable shape control andsupport components near the proximal section of a flexible and steerableelongate instrument in accordance with one embodiment.

FIG. 5A through FIG. 5D illustrate rack and pinion drive mechanisms in adrive unit or splayer for variable shape control and support inaccordance with one embodiment.

FIG. 6A through FIG. 6C illustrate the operation of a substantiallyflexible and steerable elongate instrument in accordance with oneembodiment.

FIG. 7A through FIG. 7C illustrate the operation of a substantiallyflexible and steerable elongate instrument in accordance with oneembodiment.

FIG. 8A and FIG. 8B illustrate curve aligned steering of a flexible andsteerable elongate instrument in accordance with one embodiment.

FIG. 9 illustrates the mechanics of variable shape control and supportfeatures of a flexible and steerable elongate instrument in which an “S”shaped curve may be formed in accordance with one embodiment.

FIG. 10 illustrates the mechanics of variable shape control and supportfeatures of a flexible elongate instrument in which a “J” shaped curvemay be formed in accordance with one embodiment.

FIG. 11A illustrates one embodiment of an elongate instrument withmovable or displaceable flex tubes in accordance with one embodiment.

FIG. 11B and FIG. 11C illustrate how movable flex tubes may change theproperties of an elongate instrument to form various shapes and/orcurvatures in accordance with one embodiment.

FIG. 12A through FIG. 12F illustrate a deployable and retractable anchorin accordance with one embodiment.

FIG. 13A through FIG. 13F illustrate a control unit or splayerconfigured to operate multiple flex tubes or flex members in accordancewith one embodiment.

FIG. 14A through 14D illustrate various embodiments of elongateinstruments having flex tubes located or secured at various positions orlocations along the length of the elongate instruments.

FIG. 15A through 15C illustrate a simplified construction of an elongateinstrument (1500) with variable shape control and support in accordancewith one embodiment.

FIG. 16A through 16F illustrate a sample of variations in which one setof flex tubes may be configured or implemented in a set of controllumens within the body of an elongate instrument.

FIG. 16G through FIG. 16J illustrate a sample of variations in which aplurality of flex tubes may be disposed or implemented in a controllumen of an elongate instrument.

FIG. 16I and FIG. 16J illustrate a sample of variations in which one ofthe plurality of flex tubes in a control lumen may be configured in apassively controlled manner, while one or more other flex tubes may beconfigured in a passively controlled manner, actively controlled manner,or displaceable controlled manner.

FIG. 17A through FIG. 17F illustrate various methods in which anelongate instrument with passive control, active control, ordisplaceable control may be used to approach and treat a target site ortissue structure in a minimally invasive procedure.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with thepreferred embodiments, it will be understood that they are not intendedto limit the scope of the invention to these embodiments. On thecontrary, the invention is intended to cover alternatives,modifications, and equivalents that may be included within the spiritand scope of the invention. Furthermore, in the following detaileddescription of the present invention, numerous specific details are setforth in to order to provide a thorough understanding of the presentinvention. However, it will be readily apparent to one of ordinaryskilled in the art that the present invention may be practiced withoutthese specific details.

The contents of the following applications are incorporated herein byreference as though set forth in full for all purposes: U.S. patentapplication Ser. No. 11/073,363, filed on Mar. 4, 2005; U.S. patentapplication Ser. No. 11/418,398, filed on May 3, 2006; U.S. patentapplication Ser. No. 11/637,951, filed on Dec. 11, 2006; and U.S. patentapplication Ser. No. 12/079,500, filed on Mar. 26, 2008. All of thefollowing technologies may be utilized or compatible with manually orrobotically steerable instruments, such as those described in theaforementioned U.S. patent application Ser. No. 11/073,363; U.S. patentapplication Ser. No. 11/418,398; U.S. patent application Ser. No.11/637,951; and U.S. patent application Ser. No. 12/079,500. FIG. 1illustrates one example of a robotic or telerobotic surgical system(100), e.g., the Sensei® Robotic Catheter System from Hansen Medical,Inc. in Mountain View, Calif., U.S.A., with an operator control station(102) located remotely from an operating table (104) to which anelectromechanical device, instrument driver, or robotic cathetermanipulator (RCM) (106) and instrument assembly or steerable catheterassembly (108), e.g., the Artisan™ Control Catheter also from HansenMedical, Inc. in Mountain View, Calif., U.S.A., may be supported by aninstrument driver mounting brace (110) that is mounted on the operationtable (104). A wired connection (112) transfers signals between anelectronics rack (114) near the operator control station (102) and theinstrument driver (106) mounted near the operation table (104). Theelectronics rack (114) includes system hardware and software thatoperate and perform the many functions of the robotic or teleroboticsurgical system (100). The instrument driver mounting brace (110) may bea substantially arcuate-shaped structural member configured to positionthe instrument driver (106) above a patient (not shown) who is lying onthe operating table (104). The wired connection (112) may transmitmanipulation, articulation, and control commands from an operator orsurgeon (116) who is working at the operator control station (102) andwho may be providing the necessary input to the instrument driver (106)by way of one or more input devices, such as an instinctive Motion™controller (118), joystick, keyboard (120), trackball, data gloves,exoskeletal gloves, or the like, for operating the instrument assembly(108) to perform various operations, such as minimally invasiveprocedures, on the patient who is lying on the operating table (104).The wired connection (112) may also transmit information (e.g., visual,tactile, force feedback, position, orientation, shape, localization,electrocardiogram, etc.) from the instrument assembly (108), patient,and operation site monitors (not shown in this figure) to the operatorcontrol station (102) for providing the necessary information to theoperator or surgeon (116) to facilitate monitoring the instruments,patient, and target site for performing various precise manipulation andcontrol of the instrument assembly (108) during minimally invasivesurgical procedures. The wired connection (112) may be a hard wireconnection, such as an electrical wire configured to transmit electricalsignals (e.g., digital signals, analog signals, etc.), an optical fiberconfigured to transmit optical signals, a wireless link connectionconfigured to transmit various types of wireless signals (e.g., RFsignals, microwave signals, etc.), etc., or any combinations ofelectrical wire, optical fiber, and/or wireless links. The wireconnection (112) allows the surgeon or operator (116) to be remotelylocated from the patient. The surgeon or operator (116) may be locatedacross the operation room from the patient, in a different room, in adifferent building, or in a different geographical region away fromwhere the patient is located. Information or feedback transmitted by wayof the wire connection (112) may be displayed on one or more monitors(122) at the operator control station (102).

FIG. 2A through FIG. 2D illustrate various embodiments of an instrumentassembly (108) that may be configured to perform various minimallyinvasive surgical procedures. An instrument assembly (108) may becomprised of a single steerable elongate instrument assembly or cathetersystem, as illustrated in FIG. 2A, or a combination of steerableelongate instrument assemblies or catheter systems, as illustrated inFIG. 2B through 2D. As illustrated in FIG. 2B through 2D, the steerableelongate instrument assemblies or catheter systems may be positioned ormounted in a substantially coaxial manner and configured to be operatedin a substantially coordinated or tandem-type manner or as a coordinatedor tandem-type combination. As described in the aforementioned patentapplications that have been incorporated by reference, the instrumentassembly (108) may include a control unit or splayer; which may becomprised of gears, pulleys, and control or pull wires to steer orarticulate an elongate instrument or catheter in various degrees ofmotion (e.g., up, down, pitch, yaw, or any motion in-between as well asany other motions). For example, FIG. 2A illustrates one embodiment ofan instrument assembly or catheter system (108) which includes a controlunit (202) that may be configured to steer an elongate instrument orcatheter (204). FIG. 2B illustrates another embodiment of an instrumentassembly (108) that includes a combination of steerable elongateinstrument assemblies or catheter systems which includes respectivecontrol units (202 and 212) and corresponding associated elongateinstruments or catheters (204 and 214). The elongate instrumentassemblies or catheter systems, as those illustrated in FIG. 2B as wellas other similar systems or combinations, may be positioned or mountedcoaxially with the elongate instrument or catheter of one elongateinstrument assembly or catheter system threaded or loaded through alumen of another elongate instrument assembly or catheter system. FIG.2C also illustrates an instrument assembly (108) that includes acombination of steerable elongate instrument assemblies or cathetersystems which are comprised of respective control units or splayers (222and 232) and corresponding associated elongate instruments or catheters(224 and 234). FIG. 2D illustrates another embodiment of an instrumentassembly (108) that includes a combination of steerable elongateinstrument assemblies and catheter systems which may also includerespective control units or splayers (242 and 252) and correspondingassociated elongate instruments or catheters (244 and 254).

Basic Structure of a Steerable Instrument

FIG. 3A illustrates a cross-sectional view of a section or portion of aflexible and steerable elongate instrument or catheter (300) of aninstrument assembly (108) in accordance with one embodiment. Thesteerable elongate instrument (300) may be substantially pliable orflexible such that when it is advanced into a patient, an operator orsurgeon may easily manipulate the instrument (300) to conform, adopt, ormatch the shape or curvatures of the internal pathways (e.g.,gastrointestinal tract, blood vessels, etc.) of the patient. Asillustrated, the flexible and steerable elongate instrument or catheter(300) may be comprised of multiple layers of materials and/or multipletube structures. For example, the elongate instrument (300) may includesan outer layer or outer tube (302), a main lumen, primary lumen, orcentral lumen (318) defined by an inner layer or inner tube (312), andminor, secondary, or peripheral lumens incorporated in the body of theelongate instrument (300) substantially between the outer layer (302)and the inner layer (312) where operational tubes (304), flexible tubes(306), push tubes (308), and support tubes (310) are disposed orcontained. The lumen (318) may be used to deliver one or more surgicalinstruments or tools from the proximal portion of the elongateinstrument (300) to the distal portion of the elongate instrument (300)where they maybe positioned and used to treat a target tissue structureinside a patient. The outer layer or outer tube (302) and the innerlayer or inner tube (312) may be made of any flexible, pliable, orsuitable polymer material or bio-compatible polymer material (e.g.,nylon-12, plastic, Pebax®, Pellathane, Polycarbonate, etc.) or braidedplastic composite structure. In some embodiments, outer layer or outertube (302) and the inner layer or inner tube (312) may be one layer ofmaterial or one tube structure instead of separate layers of material orseparate tube structures. Operational tubes (304) may not be actualtubes but may be the minor, secondary, or peripheral lumens or channelsthrough the body of the outer layer or outer tube (302) or theoperational tubes (304) may be separate operational tube structures thatare disposed inside the minor, secondary, or peripheral lumens orchannels in the body structure of the outer layer or outer tube (302).The operational tubes (304) may be made of any suitable polymermaterial, biocompatible polymer material or metallic material (e.g.,polyimide, stainless steel or spiral cut stainless steel, Nitinol,etc.). The separate operational tubes (304) may be melted and/or braidedinto the wall of the minor, secondary, or peripheral lumens of the outertube (302) or inner tube (312). The operational tubes (304) may providea substantially slidable surface and interface for the flex tubes (306),such that the flex tubes (306) may slide substantially freely about theinterior of the operational tubes (304) in a substantially decoupledconfiguration. In some embodiments, a distal end or portion of the flextubes (306) may be fixedly coupled to the elongate instrument. In somevariations, a proximal end or portion of the flex tubes may also befixedly coupled to the elongate instrument (300) as in a passivelycontrolled configuration of the flex tubes (306).

For example, in a passively controlled configuration, the flex tubes(306) may passively slide along the interior of the operational tubes asthe elongate instrument or catheter (300) is navigated through theanatomy, articulated or steered. As will be discussed in more detail,the slidable interface between the flex tubes (306) and the operationaltubes (304) together with buffer loops of the flex tubes in the controlunit substantially decouple the flex tubes (306) from the elongateinstrument or catheter (300). Because of the decoupled configuration ofthese two structures, articulation forces supported by the flex tubesmay be decoupled from at least a portion of the catheter body orstructure (300). As a result of decoupling the flex tubes (306) from atleast a portion the catheter body or structure, articulation forcesapplied to articulate or steer the distal portion of the elongateinstrument or catheter (300) may not be transmitted through or along thebody of the elongate instrument from the distal portion to the proximalportion of the elongate instrument, for example. Consequently, asdescribed in this example, articulation forces may be prevented orminimized from compressing the proximal portion of the elongateinstrument or catheter body; such compression if allowed to occur, mayaffect the stiffness or bending stiffness of the proximal portion of thecatheter. In addition, this decoupling of the articulation forces forthe elongate member allows that changes in the shape or length of theelongate member as it is navigated through the anatomy may not have anyimpact or minimal impact on the articulation performance of the distalsection of the elongate instrument. As will be also discussed in moredetail, in some embodiments, the flex tubes (306) may also be utilizedas support or reinforcing structures to vary or change the stiffnessand/or bend radius of at least a portion of the catheter. In particular,the flex tubes (306) may be very effective support or reinforcingstructures when they are compressed and stiffened. In other words, anelongate instrument (300) or a section of the elongate instrumentwithout any flex tubes (306) may be substantially flexible. With theintroduction of one or more flex tubes (306) into the body of theelongate instrument or a section of the elongate instrument, theelongate instrument or the section of the elongate instrument with theflex tubes (306) may become less flexible; even though the flex tubes(306) are flexible, they still have inherent axial stiffness, lateralstiffness, and bending stiffness. When the flex tubes (306) arecompressed, such as using pull wires to apply a compressible force orload to the flex tubes, for example, they may become substantially morestiff laterally, such that the stiffened structures may affect or alterthe stiffness and/or bend radius of at least a portion of the catheterwhere the flex tubes (306) are located. Accordingly, the flex tubes(306) may be utilized to vary or change the stiffness and/or bend radiusof a portion or certain portion of the catheter by changing thepositioning or placement of the flex tubes (306) in the elongateinstrument (300). For example, the flex tubes (306) may be moved fromone portion of the elongate instrument or catheter to another portion ofthe catheter. The portion from which where the flex tubes (306) weremoved may become substantially more flexible or pliable without the flextubes (306). Whereas, the portion to which where the flex tubes (306)were moved to may become substantially more stiff or less flexible orpliable. Consequently, the changes of stiffness along various portionsof the elongate instrument or catheter may substantially affect the bendradius of at least a portion of the elongate instrument as pull wiresare operated to articulate or steer the elongate instrument.

Referring back to the structural make up of the steerable instrument(300) as illustrated in FIG. 3A, the flex tubes (306) may be made from acoil of wire, a stack of rings, or a tube with spirally cut features. Asmay be appreciated, a substantially stiff tube may become less stiff ormore flexible or more pliable as a spiral cut or spirally cut feature isimparted onto a substantially stiff tube. The tube may be made from a ofa high durometer plastic such as Peek™ or stainless steel or othersuitable material. One of the features of the flex tube (306) is that itmay provide structural support to the elongate instrument (e.g., axialand lateral support) as well as being substantially flexible (e.g., ableto bend in various directions and orientations). In some embodiments,the flex tubes (306) may be constructed from one continuous coil ofwire, e.g., coil tube. In some other embodiment, the flex tube (306) maybe constructed from a stack of rings, e.g., ring tube. For a ring tube,the rings may be stacked, grouped, or maintained together in anysuitable manner. In some of the embodiments, the rings may be stacked,grouped, or maintained together by a substantially flexible sleeve,sheath, membrane, or covering. The coil of wire or rings may be madefrom a polymer material or metallic material. For example, a coil wireor rings may be made from stainless steel, Nitinol, etc. The coil wiremay be made from a round stock or a flat stock or a stock having anycross-section or profile. Similarly, the rings of the ring tube may bemade from a round stock or a flat stock or a stock having anycross-section or profile. In accordance with embodiments of the presentinvention, the flex tubes (306) may be generally constructed from asubstantially tightly wound coil of wire or a stack of rings.

Still referring to FIG. 3A, the support tubes (310) may be made of anysuitable polymer material, bio-compatible polymer material, or metallicmaterial (e.g., polyimide, stainless steel, Nitinol, etc.). The innerlayer or inner tube (312) may be made of any suitable polymer materialor bio-compatible polymer material (e.g., nylon-12, plastic, Pebax,Pellathane, Polycarbonate, etc.). In addition, the elongate instrument(300) may include a control ring (316) that may be secured near a distalportion of the elongate instrument (300). In various embodiments, theproximal end or portion of one or more pull wires (314) may beoperatively coupled to various mechanisms (e.g., gears, pulleys, etc.)of a control unit or splayer of the instrument assembly (108). The pullwire (314) may be a metallic wire, cable or thread, or it may be apolymeric wire, cable or thread. The pull wire (314) may also be made ofnatural or organic materials or fibers. The pull wire (314) may be anytype of suitable wire, cable or thread capable of supporting variouskinds of loads without deformation, significant deformation, orbreakage. The distal end or portion of one or more pull wires (314) maybe anchored or mounted to the control ring (316), such that operation ofthe pull wires (314) by the control unit or splayer may apply force ortension to the control ring (316) which may steer or articulate (e.g.,up, down, pitch, yaw, or any direction in-between) certain section orportion (e.g., distal section) of the elongate instrument (300). Inother embodiments, no control ring may be used, instead the distalportion of the pull wires may be attached directly to a section orportion of the elongate instrument (300) where it may be steered,articulated, or bent. The wires may be crimped, soldered, welded orinterlocked in any suitable manner to a specific location on a bendingsection or portion of the elongate instrument (300). The control ring(316) or the attachment point(s) may be located at any location,section, portion, or region along the length of the elongate instrument(300). Operation of the pull wires (314) may steer or articulate any ofthe location, section, portion, or region of the elongate instrument(300), which may in effect provide or define various bend radii for thearticulated portion of the elongate instrument (300). In addition, insome embodiments there may be more than one control ring (316) mountedor installed to the elongate instrument (300) or more than one controlwire attachment control locations, sections, or portions forcontrolling, steering, or articulating more than one section or portionof the elongate instrument (300). As will be described further, theflexible and steerable elongate instrument (300) having more than onecontrol rings (316) or more than one control sections may be steered,articulated, or deflected into various complex shapes or curvatures(e.g., “S” curved shapes or “J” curved shapes, etc.). For example, thesteerable elongate instrument (300) may be steered, articulated, ordeflected into various complex shapes or curvatures that may conform tovarious complex shapes or curvatures of internal pathways of a patientto reach a target tissue structure of an organ inside the patient.

In some embodiments, one or more portions of the flex tubes (306) may beincorporated or coupled to the wall of the catheter (300) and suchincorporation or coupling may be used for multiple functional purposes.For example, the coupling of the flex tubes (306) to the elongateinstrument (300) may be used to support articulation forces as theelongate instrument or catheter is steered or articulated. As one ormore of the pull wires (314) are operated by the control unit to steeror articulate the elongate instrument (300), the articulation orsteering forces may be substantially transmitted along the body of theelongate instrument (300) from the portion (e.g., distal portion) of theelongate instrument (300) where the distal end or portion of the pullwires (314) may be anchored to the proximal portion of the elongateinstrument (300). Since the flex tubes (306) are incorporated or coupledto the wall of the elongate instrument (300) and the flex tubes (306)are substantially configured to support axial loading, the articulationor steering loads may be decoupled from the elongate instrument (300) atthe point or location where the flex tubes (306) are incorporated orcoupled to the wall of the elongate instrument (300). Hence, theproximal portion of the elongate instrument may be substantiallyunaffected by the articulation or steering of the particular section orportion (e.g., distal section or portion) of the elongate instrument(300). The proximal portion of the elongate instrument may remainsubstantially flexible and pliable even when a particular portion (e.g.,distal portion) of the elongate instrument is being articulated orsteered. As such, an operator or surgeon may easily manipulate theelongate instrument (300) and urge it to conform, adopt, or match thevarious shape or curvatures of the internal pathways of a patient whilethe elongate instrument is being advanced and steered to reach varioustissue structures or target sites inside a patient. in another exampleor application of the elongate instrument (300), the flex tubes (306)may be used as a structural support member to the catheter (300); inparticular, when the flex tubes are stiffened by tensioning pull wiresthat may be attached to the flex tubes (306). In such application, theflex tubes (306) may support not only axial forces or loads, but alsolateral forces or loads. As such, the flex tubes may increase thelateral as well as bending stiffness of at least a portion or section ofthe elongate instrument (300). In addition, the flex tubes (306) mayalso affect the bending radius of at least a portion or section of theelongate instrument (300) as the elongate instrument is steered,articulated, or manipulated.

FIG. 3B illustrates another cross-sectional view (View 1-1) of a sectionor portion of a steerable elongate instrument or catheter (300). Asillustrated in FIG. 3B, the components of the elongate instrument (300)may be contained within or between the outer layer of material or outertube (302) and the inner layer of material or inner tube (312). Aprimary, main, central, or working lumen (318) may be provided ordefined by the inner layer of material or inner tube (312). The mainlumen or central lumen (318) may be used to pass surgical instrumentsfrom the proximal end to the distal end of the elongate instrument (300)for performing various minimally invasive surgical procedures. Many ofthe components of the elongate instrument (300), e.g., operational tubes(304), flexible tubes (306), push tubes (308), and support tubes (310),are disposed within the minor, secondary, or peripheral lumens in thebody structure of the elongate instrument, as illustrated in FIG. 3A andFIG. 3B. In some embodiments, one or more pull wires (314) may bedisposed within lumens of the support tubes (310), lumens of the flextubes (306), and lumens of the push tubes (308). As illustrated in FIG.3A, the distal end or portion of the support tubes (310) may be securedor anchored near the distal portion of the elongate instrument (300) andthe proximal end of the support tubes (310) may be slidably coupled tothe distal end or portion of the flex tubes (306). In one embodiment,the distal portion of the flex tubes (306) may be secured at respectiveanchor points or regions (320) of the elongate instrument (300).Anchoring the flex tubes (306) to the elongate instrument (300) mayprovide the connections or couplings that allow force or load to betransferred from the flex tubes (306) to the elongate instrument (300)when force or load is applied to the flex tubes. For example, in someembodiments the flex tubes (306) may be actively controlled, that is oneor more push tubes (308) or control members (308) may be configured topush against respective flex tubes (306). The applied force from thepush tubes or control members (308) may be transmitted by way of theanchoring points (320) through the flex tubes (306) to the elongatedinstrument (300). In this way, at least a portion of the elongateinstrument (300) may be steered or shaped by the push tubes or controlmembers (308). Similarly, articulation or steering forces or loads maybe transferred or coupled at the anchor points (320) from one portion(e.g., distal portion) of the elongate instrument (300) to the flextubes (306), such that the flex tubes (306) may act as load bearingsupport elements for another portion (e.g., proximal portion) of theelongate instrument (300) where the force or load may be decoupled ornot transmitted. In other words, the anchor points (320) may function ascoupling points from one portion (e.g., distal portion) of the elongateinstrument (300) to the flex tubes (306) where force or load may betransferred from one portion (e.g., distal portion) of the elongateinstrument to the flex tubes. Similarly, the anchor points (320) mayalso function as decoupling points between one portion (e.g., distalportion) of the elongate instrument (300) to another portion (e.g.,proximal portion) of the elongate instrument (300) where force or loadmay be decoupled or not transferred from one portion (e.g., distalportion) of the elongate instrument to another portion (e.g., proximalportion) of the elongate instrument. As will be discussed in moredetails, the location of the anchor points (320) may be varied tocontrol the radius of curvature of a bending section of the elongateinstrument (300) as the elongate instrument is articulated or steered.In some embodiments, the flex tubes (306) may be anchored atsubstantially the same points or regions of the elongated instrument(300). In some embodiments, the flex tubes (306) may be anchored atsubstantially different points or regions of the elongate instrument(300) to affect the bend radius of various portions of the elongateinstrument (300) and/or various directions of steering or bending. Theflex tubes (306) may be secured to the elongate instrument (300) in anysuitable manner. In some embodiments, the distal portion of the flextubes (306) may be fused with the material of the outer layer or outertube (302), such as by thermal fusion. Similarly, the material of theouter layer or outer tube (302) may be fused to the flex tubes (306).For example, the flex tubes (306) may be fused to the outer layer orouter tube (302) at various places where it is not covered by theoperational tubes (304), as illustrated in FIG. 3A. In some embodiments,the elongate instrument may be configured with displacement control ofthe flex members (306). That is a flex tube (306) may not be fixedlycoupled to the elongate instrument, instead it may be displaced alongthe length of the elongate instrument (300). Once the flex tube (306) isdisplaced to a desired location, the distal portion of the flex tube(306) may be secured or coupled to the elongate instrument (300) by adeployable and retractable anchor. The displacement of proximal portionof the flex tube (306) may be controlled by the push tube or controlmember (308). The deployable anchor may be deployed to couple the flextube (306) to a particular anchor point at a particular location on theelongate instrument. The anchor may also be retracted such that the flextube (306) may be disengaged or separated from the elongate instrument(300) such that it may be displaced to a different location along theelongate instrument (300).

Passively Controlled Flex Member

As illustrated in FIG. 4A, an elongate instrument (300) with passivelycontrolled flex members (300) may be similarly configured as theelongate instrument structure illustrated in FIG. 3A with the exceptionthat the proximal portion of the flex members (300) may be fixedlycoupled to the body of the elongate instrument, the control unit orsplayer, or some other structural element or component. In someembodiments, the push tube or control member (308) may not be includedas a component of the elongate instrument (300) for a passivelycontrolled flex member. In the passively controlled configuration, theflex members (306) may include a service or buffer loop (402), as moreclearly illustrated in FIG. 4B. The service loop or buffer loop (402) onthe flex members (306) may provide the extra service length or bufferlength needed for articulation as the elongate instrument (300) ispushed through the anatomy, articulated or steered.

As the elongate instrument is pushed through the anatomy, steered orarticulated, the support tubes (310) in the distal section may slidealong the flex tubes (306) as indicated by the arrows in FIG. 4C. Thesupport tubes (310) may provide a lumen or path for the pull wires (314)to connect to the distal section of the catheter. The support tubes(310) may also provide some amount of structural rigidity or support tothe distal portion of the elongate instrument (300). In someembodiments, the elongate instrument (300) may not include any supporttubes (310). In some embodiments, one or more flex tubes (306) may beextended further into the distal portion of the elongate instrument(300) to provide some structural rigidity or support to the distalportion of the elongate instrument. In some embodiments, the flex tubes(306) may be substantially more stiff or more rigid than the supporttubes (310), such that when one or more flex tubes (306) are used assupport structures to reinforce the distal portion of the elongateinstrument (300), the distal portion of the elongate instrument may besubstantially more stiff or more rigid than when it is supported by thesupport tubes (310). In some embodiments, the flex tube (306) mayprovide substantially the same or similar stiffness or structuralsupport as the support tubes (310), such that there may not be anysignificant difference if the flex tubes (306) or support tubes (310)are used to provide structural support to the distal portion of theelongate instrument (300). In some embodiments, the flex tubes (306) maybe substantially more flexible than the support tubes (310), such thatthe distal portion of the elongate instrument may be substantially moreflexible or less rigid than when it is supported by the flex tubes(306).

Referring back to FIG. 4A, the flex tubes (306) may be slidably coupledto the operational tubes (304) while fixed at the distal end (320). Asthe elongate instrument (300) is steered or articulated, or as thecatheter is advanced through the natural curvature of the body lumens,the flex tubes (306) may slide along the operational tubes (304) asindicated by the arrows illustrated in FIG. 4D. In one scenario, forexample, the elongate instrument (300) may be steered by operating orapplying tension to one of the pull wires (e.g., 314A) through operationof one or more gears and/or pulleys in the control unit or splayer. Thetension on one of the pull wires (e.g., 314A) may cause the elongateinstrument (300) to bend, as illustrated in FIG. 4D. The inside edge orinside region of the bend may be contracted or foreshortened, while theoutside edge or outside region of the bend may be lengthened orstretched. The bend of the elongate instrument as described may causeone of the flex tubes (e.g., 306A) to slide “out” near the proximalportion of the elongate instrument (300) at the contracted orforeshorten edge or region. In this same example, another one of theflex tubes (e.g., 306B) may slide “in” near the proximal portion of theelongate instrument (300) at the lengthened or stretched edge or region,as illustrated in FIG. 4D. In order to accommodate the sliding of “in”and “out” of the flex tubes (306), the flex tubes may include a serviceloop or buffer loop (402) to allow for these “in” and “out”displacements or movements of the flex tubes (306). As discussed, theflex tubes (306) may be passively constrained or restrained. The flextubes (306) may be constrained or restrained by being coupled to theelongate instrument (300), the control unit, or splayer. In addition,the flex tubes (306) may be constrained or restrained by hard-stops,tethers, etc. In some embodiments, the operational tubes (304) may beconfigured or allowed to float or slide substantially freely relative tothe outer layer or outer tube (302). In some other embodiments, theoperational tubes (304) may not be configured or allowed to float orslide substantially freely relative to the outer layer or outer tube(302).

Actively Controlled Flex Member

In some embodiments, the flex member (306) of an elongate instrument maybe actively controlled. For example, the distal portion of the flexmember (306) may be coupled to the body of an elongate instrument, whilethe proximal portion of the flex member (306) may be displaced or movedby various control mechanisms or members of the elongate instrumentassembly or system. In some embodiments, the proximal portion of theflex members (306) may be displaced by push tubes or control members.The push tubes or control members may be operated by mechanisms of aninstrument assembly, control unit, or splayer of an elongate instrumentassembly or catheter system. A control unit or splayer in an elongateinstrument assembly or catheter system may include drive mechanisms thatare configured to operate or drive the push tubes or control members. Inone example, as illustrated in FIG. 5A through 5D, the drive mechanismsin a control unit (502) of a catheter system (500) may include racks(508) and pinions (510) for operating or driving the push tubes (506) orcontrol members (506). In some embodiments, the pinions (510) may beoperated by output torque provided by the instrument driver (106) of arobotic or telerobotic surgical system (100). In some embodiments, thepinions (510) may be operated by output torque provided by variousmechanical or manually operated systems. Other drive mechanisms may alsobe configured to operate or drive the push tubes, e.g., rotary gears,worm gears, linear gears, etc. FIG. 5A illustrates an exposed view of acontrol unit or splayer (502) of an elongate instrument assembly orcatheter system (500). A close-up view (View 2-2) of the control unit(502) is illustrated in FIG. 5B. As illustrated in FIG. 5B in View 2-2,push tubes (506) or control members (506) may be controlled or driven byracks (508) and pinions (510) in a “forward” or “backward” manner,movement or displacement, so as to apply or release force exerted ontothe flex tubes (506) of a steerable elongate instrument or catheter(504). As the racks (508) are driven “forward”, the flex tubes (506) maybe driven forward and they may also be compressed in the axialdirection. The “forward” displacement of the flex tubes (506) may applyan axial load to the distal section of the elongate instrument orcatheter (504). This axial load may cause the distal section of thecatheter (504) to bend, deflect, steer, or articulate at a particularposition or location of the catheter. Since the flex tubes (506) may beanchored or secured at the distal section, compression force applied atthe proximal section by the racks (508) may cause at least a portion,e.g., distal portion, of the elongate instrument or catheter (504) tobend, deflect, steer, or articulate in response to the compression forceexerted by the racks (508) and form a particular induced shape ororientation. Accordingly, active control of the push tubes (506) mayallow “shaping” or putting the elongate instrument or catheter (504)into various shapes or curvatures. The elongate instrument or catheter(504) or portion (e.g., proximal portion) of the catheter (504) may beinduced and then locked in place by the push tubes (506) into variousshape or curvatures that may substantially match the natural pathways oranatomy where the elongate instrument or catheter may be used in aminimally invasive procedure. In addition, another portion (e.g., distalportion) of the catheter may be articulated or steered by pull wires tonavigate the catheter (504) through torture pathways inside the patient.

FIG. 5C illustrates another exposed view of a catheter system (500). Asillustrated in FIG. 5C, drive pins (512), which may be engaged to atorque output system (e.g., instrument driver), provide the necessarytorque or motion to operate the pinions (510) for controlling or drivingthe racks (508) in a “forward” or “backward” manner, movement, ordisplacement. The forward and backward movements of the racks (508) maybe used to actively control or operate the push tubes (506). FIG. 5Dillustrates a close-up view (View 3-3) of the racks (508) and push tubes(506). The drive mechanisms in the instrument driver may operate eachset of racks (508) and pinions (510) independently or in concert in acoordinated manner. As such, the push tubes or control members (506) maybe operated independently or in concert in a coordinated manner to applyor release force or tension on the flex tubes (506).

FIG. 6A through FIG. 6C illustrate the operation of a substantiallyflexible and steerable elongate instrument in accordance with oneembodiment. FIG. 6A illustrates an elongate instrument (600) of aninstrument assembly in a substantially neutral state. In this example,the elongate instrument (600) includes an outer body (602), two sets ofsupport tubes (not shown), operational tubes (604A and 604B), flex tubes(606A and 606B), and pull wires (608A and 608B). Each set of supporttubes, operational tubes (604A and 604B), flex tubes (606A and 606B),and pull wires (56A and 568B) may be substantially axially aligned, andthe pull wires (608A and 608B) may be coupled to a control ring (notshown) or mounting points that are located at the distal section orportion of the elongate instrument (600). As illustrated in FIG. 6A, inthe neutral state the flex tubes (606A and 606B) and pull wires (608Aand 608B) may extend out of the operational tubes (604A and 604B) atabout the same amount or distance. As the substantially flexible andsteerable elongate instrument (600) is advanced into the anatomy andnatural pathway (e.g., blood vessel, gastrointestinal tract, etc.) of apatient, it may take on the shape of the natural pathway, as illustratedin FIG. 6B. In this example, the proximal section (610) of the elongateinstrument may be bent at a curvature induced by the natural pathway(e.g., blood vessel, gastrointestinal tract, etc.), while the distalsection (620) may remain relatively straight or in a substantiallyneutral state. Due to the bend at the proximal section (610), the flextube (606A) and pull wire (608A) may slide “out” of the operational tube(604A) near the inside edge or inside region of the bend as it may becontracted or foreshortened, as indicated by the arrow illustrated inFIG. 6B. At the same time, due to the bend at the proximal section(610), the flex tube (606B) and pull wire (608B) may slide “in” to theoperational tube (604B) near the outside edge or outside region of thebend as it may be lengthened or stretched, as indicated by the arrowillustrated in FIG. 6B. As may be appreciated, it may be advantageous tomaintain the induced shape or curvature of the proximal section (610) ofthe elongate instrument (600) and at the same time articulate or steerthe distal section (620) of the elongate instrument (600) to treat atarget site or toward a different direction down the natural pathway. Asillustrated in FIG. 6C, the shape or curvature of the proximal section(610) of the elongate instrument (600) may be maintained or locked bysecuring the distal ends of the flex tubes (606A and 606B) into theposition they have acquired due to the induced shape or bend of theproximal section (610). The flex tubes (606A and 606B) may be locked inplace by using the active control feature of the instrument assemblyprovided by the various mechanisms (e.g., rack and pins, drive gears,etc.) in the control unit or splayer. While the elongate instrument(600) may be inherently substantially flexible, the elongate instrumentor portion of the elongate instrument may become substantially stiff orrigid when the flex tubes are compressed or locked through activecontrol. Once the flex tubes are locked in place, they may becomesubstantially stiff or rigid structures or platforms. As the flex tubeshave been locked in place to maintain the induced shape or curvature ofthe proximal section (610), pull wires (608A and 608B) may be operatedto steer or articulate the distal section (620) of the elongateinstrument (600). In this example, pull wire (608B) may be pulled ortensioned, as indicated by the arrow illustrated in FIG. 6C, to steerthe distal section (620) in a substantially opposite direction of thebend in the proximal section (610). The pull wire (608A) may be relaxed,as indicated by the arrow illustrated in FIG. 6C, to accommodate for thebend at the outside edge or outside region of the bend of the distalsection (620). In addition, the bending force or load of the distalsection (620) may be substantially absorbed or transferred from theelongate instrument through the flex tube attachment points and then tothe flex tubes (606A and 606B), which may be further transferred to thecontrol unit or splayer of the instrument assembly. The proximal section(610) of the elongate instrument (600) may not be affected by thesteering or articulation forces applied by the pull wire to steer thedistal section (620) of the elongate instrument (600).

In another example, as illustrated in FIG. 7A through FIG. 7C, theproximal section (610) of the elongate instrument may be bent at acurvature induced by the bending, steering, or articulation of thedistal section (620) of an elongate instrument (600). FIG. 7Aillustrates an elongate instrument (600) of an instrument assembly in aninitial substantially neutral state. In this example, the elongateinstrument (600) includes an outer body (602), two sets of support tubes(not shown), operational tubes (604A and 604B), flex tubes (606A and606B), and pull wires (608A and 608B). Each set of support tubes,operational tubes (604A and 604B), flex tubes (606A and 606B), and pullwires (608A and 608B) may be substantially axially aligned, and the pullwires (608A and 608B) may be coupled to a control ring (not shown) ormounting points that are located at the distal section or portion of theelongate instrument (600). As illustrated in FIG. 7A, in the neutralstate the flex tubes (606A and 606B) and pull wires (608A and 608B) mayextend out of the operational tubes (604A and 604B) at about the sameamount or distance. The substantially flexible and steerable elongateinstrument (600) may be steered or articulated at the distal section byoperation of the pull wires (608A and 608B), as illustrated in FIG. 7B.In this example, the proximal section (610) of the elongate instrumentmay be bent at a curvature induced by the bending, steering orarticulation at the distal section (620). The induced bend and curvatureat the proximal section (610) may be locked in place by using the activecontrol feature of the instrument assembly provided by the variousmechanisms (e.g., rack and pins, drive gears, etc.) in the control unitor splayer as previously described. While the elongate instrument (600)may be a substantially flexible instrument, the proximal section (610)may become substantially stiff or rigid as the flex tubes (606A and606B) are locked in place, and proximal section (610) may become asubstantially rigid platform to support the manipulation or articulationof the substantially flexible distal section (620). As a result, theflex tubes may act as support structures of the elongate instrument. Theability to lock various sections of the elongate instrument intoparticular shapes or curvatures by means of the flex tubes allow theelongate instrument to be manipulated into substantially complex shapesor curvatures (e.g., “S” shaped curves, “J” shaped curves, etc.). Inthis example, pull wire (608B) may be pulled or tensioned, as indicatedby the arrow illustrated in FIG. 7C, to steer the distal section (620)in a substantially opposite direction of the bend in the proximalsection (610).

In other embodiments of an elongate instrument where flex tube orsimilar control or support structure may not be used, operating ortensioning a pull wire on the outside edge of a bend may cause theelongate instrument to rotate or twist as the pull wire may tend torotate the distal section of the elongate instrument until the pull wireis at the inside edge of the bend; this rotation or twist phenomenon oroccurrence is known as curve alignment. Embodiments of the presentinvention may substantially eliminate this problem by providing supportstructures such as flex tubes that could prevent curve alignment andsubstantially prevent or eliminate unwanted rotation or twist of thecatheter. In other words, the pull wires, flex tubes, and the distalanchor points of the pull wires at the control ring or the body of theelongate instrument may all be substantially aligned, such thatoperating or tensioning of the pull wires would allow the elongateinstrument to bend in a substantially aligned or neutral configurationwith the longitudinal axis of the pull wire and flex tube. In thisconfiguration, there may not be any component or vector of force or loadthat could cause the elongate instrument to rotate or twist resulting incurve alignment as the elongate instrument is steered or bent. FIG. 8Aand FIG. 8B illustrate one embodiment of an elongate instrument orcatheter (800) that substantially eliminate or prevent curve alignmentand the catheter may be biased, steered, or articulated in specificplanes, e.g., X-Plane, Y-Plane, Z-Plane, of articulation by using flextubes as support structures or “backbones” that may be in substantialalignment with a neutral axis. As illustrated in FIGS. 8A and 8B, thepull wires may be substantially aligned with the neutral axes, e.g., inthe X-Y Planes. In FIG. 8A, as a pull wire is operated (indicated by thearrow) to steer the elongate instrument, the flex tube supports the pullwire, maintain its alignment to the longitudinal axis, and prevent itfrom moving to the inside edge of the bend, which may produce a forcevector that could cause the elongate instrument to twist or rotate. Inthis example, the operation of the pull wire causes the distal sectionof the elongate instrument to be steered or articulated in asubstantially upward movement, e.g., the direction or vector ofarticulation is in the Y-Plane. Similarly, as illustrated in FIG. 8B, asa pull wire is operated (indicated by the arrow) to steer the elongateinstrument, the flex tube supports the pull wire, maintain its alignmentto the longitudinal axis, and prevent it from moving to the inside edgeof the bend, which may produce a force vector that could cause theelongate instrument to twist or rotate. In this example, the operationof the pull wire causes the distal section of the elongate instrument tobe steered or articulated in a substantial sideway or rightwardmovement, e.g., the direction or vector of articulation is in theX-Plane.

As described, embodiments of the present invention may allow a flexibleand steerable elongate instrument to execute various movements necessaryto form variable or changeable shapes and curvatures. For example, FIG.9 illustrates one embodiment in which a complex “S” shaped curvature maybe formed with an elongate instrument (900). In this example, theelongate instrument (900) may include a first flex tube (906-1) whichmay be disposed inside a lumen of a first operational tube (904-1). Thefirst operational tube (904-1) may terminate near a first anchor pointor region (920-1), where the first flex tube (906-1) may be secured,fused, or bonded to the material of the elongate body (900), asillustrated in a first detail view (View 4-4) of FIG. 9. A first pullwire (914-1) may be disposed through a lumen of the flex tube (906-1)and a first support tube (910-1), wherein the proximal end of the firstpull wire (914-1) may be operatively coupled to a control unit orsplayer (not shown) and the distal end of the first pull wire (914-1)may be anchored to a control ring (916-1) or an anchor point on the bodyof the elongate instrument (900), as illustrated in a second detail view(View 5-5) of FIG. 9. The support tube (910-1) may be slidably coupledto the first flex tube (906-1), such that it may slide along the surfaceof the first flex tube as the elongate instrument is steered orarticulated. The elongate instrument (900) may include a second flextube (906-2) which may be disposed inside a lumen of a secondoperational tube (904-2). The second operational tube (904-2) mayterminate near a second anchor point or region (920-2), where the secondflex tube (906-2) may be secured, fused, or bonded to the material ofthe elongate body (900), as illustrated in the second detail view (View5-5). A second pull wire (914-2) may be disposed through a lumen of thesecond flex tube (906-2) and a second support tube (910-2), wherein theproximal end of the second pull wire (914-2) may be operatively coupledto a control unit or splayer (not shown) and the distal end of thesecond pull wire (914-2) may be anchored to a second control ring(916-2) or an anchor point on the body of the elongate instrument (900),as illustrated in FIG. 9. The second support tube (910-2) may beslidably coupled to the second flex tube (906-2), such that it may slidealong the surface of the second flex tube as the elongate instrument issteered or bent. Although two flex tubes and associated components areillustrated in FIG. 9, additional number of flex tubes and associatedcomponents, e.g., 2 or more sets of flex tubes and associatedcomponents, may be used to steer and control the movement as well as theshape of the elongate instrument.

As illustrated in FIG. 9, the first or lower portion of the “S” may beformed by the proximal portion of the elongate instrument (900). Thelower portion of the “S” may be obtained by operating the first pullwire (914-1) to steer the proximal portion of the elongate instrument(900) into a curvature that resembles the shape of the lower portion ofthe “S” shape. The lower portion of the “S” shape formed by the proximalportion of the elongate instrument may be locked in place by locking thesecond flex tube (906-2) in the position it has acquired by variouscontrol means (e.g., active control mechanisms of the control unit orsplayer). Once the proximal portion of the elongate instrument has beenlocked in place, the second pull wire (714-2) may be operated to steeror bend the distal portion of the elongate instrument (900) into acurvature that resembles the upper portion of the “S” as illustrated inFIG. 9.

Another complex shape may be formed by an elongate instrument inaccordance with another embodiment. FIG. 10 illustrates a complex “J”shaped curvature formed by an elongate instrument (1000). In thisexample, the elongate instrument (1000) may include two set of flextubes and their associated components. As illustrated in FIG. 10, the“J” shaped curvature may be formed from three sections of the elongateinstrument (1000). The first section (1002-1) may be substantiallystraight to form the straight portion of the “J”, the second section(1002-2) may form a first bend section of the first curvature or initialcurvature of the “J”, and the third section (1002-3) may form the secondbend of the second or final curvature of the “J”. As illustrated in FIG.10, the elongate instrument (1000) may include two flex tubes (1006-1and 1006-2). The first flex tube (1006-1) may operate as a supportstructure to provide the support (e.g., lateral stiffness or support)necessary to form or maintain the straight portion of the “J”. Similarto the construction of other embodiments as previously described, thedistal end of flex tube (1006-1) may be anchored to the elongate bodynear the distal section of first section (1002-1) of the elongate bodywhere it may not be covered by the operational tube (1004-1). Activecontrol as previously described may be used to apply force or load tocompress the flex tube (1006-1), such that the flex tube may become asubstantial rigid or stiff structure. Since compression force wasapplied to the flex tube (1006-1) when it was in a substantially neutralstate without having been deflected, steered, or articulated, the flextube (1006-1) may be maintained or stiffened in its neutral orsubstantially straight configuration. In its compressed or substantiallystiffened or rigid state, the flex tube (1006-1) may be used to supportthe deflection or articulation of the second section (1002-2) of theelongate instrument. The second section (1002-2) may be deflected orarticulated by operating the pull wire (1014-1). The distal end of thepull wire (1014-1) may be anchored to a control ring (1016-1) or ananchoring point near the distal portion of the second section (1002-2).The proximal end of the pull wire (1014-1) may be operatively coupled toa control unit or splayer (not shown) that operates the pull wire. Oncethe desired curvature of the second section (1002-2) is achieved, theshape of the curvature may be locked in place by compressing and/orlocking the second flex tube (1006-2) in place using active control aspreviously described. The distal end of the second flex tube (1006-2)may be anchored to the elongate instrument near the distal portion ofsecond section (1002-2) where it may be exposed out of the secondoperational tube (1004-2). Once the second flex tube (1006-2) is lockedin place and becomes a substantially stiffened or rigid structure, thesecond pull wire (1014-2) may be operated to steer or articulate thethird section (1002-3) into the desired curvature to form the “J” shape.The distal end of the second pull wire (1014-2) may be anchored to thesecond control ring (1016-2) or to an anchor point on the elongate bodynear the distal portion of the third section (1002-3). The proximal endof the second pull wire (1014-2) may be operatively coupled to a controlunit or splayer (not shown) that operates the pull wire. Although twoexamples of complex shapes or curvatures may be formed by a flexible andsteerable elongate body with variable or changeable shape control andsupport elements as illustrated and described, many other complex shapesor curvatures may be form by an elongate body in accordance with variousembodiments of the present invention.

Displaceable Flex Member

FIG. 11A illustrates another embodiment of a flexible and steerableelongate instrument in accordance with another embodiment of the presentinvention. In this embodiment, the flex tubes (1106-1 and 1106-2) may beallowed to slide along the length of the elongate instrument (1100).That is, the flex tubes (1106-1 and 1106-2) may not be fixedly securedto the elongate instrument (1100), instead the flex tubes may include adeployable and retractable anchor that allows the flex tubes to bedisplaced. As such, the position of the flex tubes (1106-1 and 1106-2)may be changed substantially along the length of the elongate instrument(1100). The positions of the flex tubes (1106-1 and 1106-2) may bechanged by operating various pull wires (1124-1 and 1124-2), push tubes(not shown), and active control elements. Pull wires (1124-1 and 1124-2)may be secured near the distal portion of the flex tubes (1106-1 and1106-2), as illustrated in detail view (View 6-6), and the pull wires(1124-1 and 1124-2) may be used to control the displacement of the flextubes. The other pull wires (1114-1 and 1114-2) may be extended andcoupled to a control ring or the distal portion of the elongateinstrument for steering or articulating the distal section of theelongate instrument. The pull wires may be flat wires, round wires, orwires having any suitable shape, cross section, or profile. Because theflex tubes (1106-1 and 1106-2) may not be secured, they may be moved orpushed further toward the distal portion of the elongate instrument(1100) by the respective push tubes or pulled back toward the proximalportion of the elongate instrument (1100) by the respective pull wires(1124-1 and 1124-2). The ability to move the flex tubes along the lengthof an elongate instrument provides greater variability and control ofthe possible shapes or curvatures that may be formed with the elongateinstrument. In addition, the displacement of the flex tubes may alsochange the stiffness (e.g., lateral stiffness, bending stiffness) of atleast a portion of the elongate instrument. The displacement of the flextubes as it may affect the stiffness of at least a portion of theelongate instrument may also change or affect the radius of curvature ofa least a portion of the elongate instrument as the elongate instrumentis articulated or steered. By using the drive mechanisms in the controlunit or splayer, the flex tubes (1106-1 and 1106-2) may be movedseparately or in concert in a coordinated manner.

FIG. 11B and FIG. 11C illustrate one example of moving or displacing theflex tubes to alter the variability, shape, or curvature of an elongateinstrument (1100) as well as an angle of trajectory (a) between twosections or portions of the elongate instrument (1100). As illustratedin FIG. 11B, the flex tubes (1106-1 and 1106-2) may be positioned alongthe length of the elongate instrument (1100) up to the location near thedistal portion of the first section (1102-1). As illustrated in FIG. 11Cand indicated by the first set of arrows (11C-1), the flex tubes (1106-1and 1106-2) may be moved back toward the proximal end of the elongateinstrument (1100). As illustrated, the first section (1102-1) of theelongate instrument (1100) may have become substantially shorter ascompared to its initial state as illustrated in FIG. 11B when the sameor substantially the same amount of force may be applied to steer orarticulate the distal end or portion (1102-2) of the elongate instrument(1100). Correspondingly, the second section (1102-2) may have becomesubstantially longer as compared to its initial state as illustrated inFIG. 11B. In addition, an angle of trajectory (a1) between the firstsection (1102-1) and the second section (1102-2), as illustrated in FIG.11B, may have also changed to a different angle of trajectory (a2), asillustrated in FIG. 11C. As the flex tubes (1106-1 and 1106-2) are movedback toward the proximal end of the elongate instrument (1100), thedistal portion of the elongate instrument has lost some of it supportand rigidity provided by the flex tubes (1106-1 and 1106-2). As a forceor load is applied to steer or articulate the elongate instrument(1100), the less supported or more flexible distal portion of theelongate instrument may form a substantially larger or longer arc orcurvature as illustrated by a substantially larger or longer secondsection (1102-2) in FIG. 11C, than the arc or curvature that may beobtained in its initial state illustrated in FIG. 11B. Accordingly,changing the position or location of the flex tubes along the length ofan elongate instrument may allow the elongate instrument to change itscharacteristic properties of being able to form various shapes and/orcurvatures as well as angle of trajectory (a) between two sections,portions or segments of elongate instrument. As illustrated in thisexample, displacement of the flex tubes (1106-1 and 1106-2) may alterthe stiffness of a portion of the elongate instrument (1100). As theflex tubes (1106-1 and 1106-2) have certain amount of axial and lateralstiffness, displacing the flex tubes may affect the stiffness, e.g.,axial and lateral stiffness, of at least a portion of the elongateinstrument (1100). As may be appreciated, the variation or change ofstiffness of a portion of the elongate instrument may affect the radiusof curvature of at least a portion of the elongate instrument as forceor load is applied to steer or articulate the elongate instrument. Thedisplaced flex tubes may be locked in-place by using a deployable andretractable anchor in combination with push tubes or control members.The anchor then allows the flex tubes to serve as passive coils andabsorb or bear the articulation loads and isolate or decouple theelongate body from the articulation loads. As such, the altered shape,curvature, and/or angle of trajectory (a) of the elongate instrument maybe maintained for various purposes. For example, the altered shape,curvature, and/or angle of trajectory (a) may be maintained tofacilitate advancement of the elongate instrument through a particularsection of a tortuous pathway. in addition, the altered shape,curvature, and or angle of trajectory (a) may be maintain to facilitateadvancement of certain objects, surgical instrument, etc. through aworking lumen of the elongate instrument to a target tissue structureinside a patient.

The overall stiffness of at least a portion of the elongate instrumentmay be further altered or changed by compressing the flex tubes (1106-1and 1106-2). The second set of arrows (11C-2) indicates that compressionforces may be applied to stiffen the flex tubes (1106-1 and 1106-2) andprovide substantially rigid structures to support steering orarticulation of the second section (1102-2) of the elongate instrument(1100) by operating the pull wires (1114-1 and 1114-2) as indicated bythe third set of arrows (11C-3) in FIG. 1 IC as the flex tubes (1106-1and 1106-2) are supported by corresponding push tubes or control members(not shown).

Deployable and Retractable Anchor

FIG. 12A through FIG. 12F illustrate one embodiment of a deployable andretractable anchor for a displaceable flex tube or flex member of anelongate instrument. FIG. 12A illustrates the deployable and retractableanchor (1200) in its neutral state. That is, the anchoring mechanismsmay not be deployed. FIG. 12B illustrates a close-up view of thedeployable anchor (1200) in its neutral state, as shown in detail view(View 7-7). FIG. 12C illustrates the deployable anchor (1200) in itsactivated state. That is, the anchoring mechanisms are deployed orextended in engagement or coupling mode. FIG. 12D illustrates a close-upview of the deployable anchor (1200) in its activated state, as shown indetail view (View 8-8). Referring back to FIG. 12A, the deployable andretractable anchor (1200) may be coupled to a distal end or portion of aflex tube (1206). A distal end of an anchor wire or pull wire (1214-2)may be coupled to the deployable anchor (1200) and a proximal end of theanchor wire or pull wire (1214-2) may be coupled to a control unit (notshown). The control unit may be configured to operate the anchor wire(1214-2) to activate the deployable anchor (1200), such as tensioningthe anchor wire, as well as operate the anchor wire (1214-2) tode-activate the deployable anchor, such as releasing the tension on theanchor wire. The anchor wire (1214-2) may be configured to operate themechanisms of the deployable anchor, such as the distal anchor puck(1224) to operate various cam pins (1228) to travel along the campathways (1230) and then displace the anchoring cams (1222) to engage ordisengage the deployable anchor (1200) from the body of the elongateinstrument or catheter (not shown). The anchoring cams (1222) may bedisplaced upward to engage the body of the elongate instrument ordownward to disengage the anchor (1200) from the body of the elongateinstrument or catheter. A pull wire or control wire (1214-1) may bedisposed through the flex member (1206) and the deployable anchor (1200)to a distal portion of the elongate instrument for steering orarticulating the elongate instrument. As shown in more detail in FIG.12E and FIG. 12F, distal anchor puck (1224) and proximal anchor puck(1226) support the anchor wire (1214-2). As the anchor wire is operated,e.g., tensioned by a control unit or splayer, the distal anchor puck(1224) may be displaced toward the proximal portion of the anchor(1200). The displacement of the anchor puck (1224) toward the proximalportion of the anchor (1200) may cause the cam pins (1228) to travelalong the cam pathways (1230) which may cause the anchoring cams (1222)to be displaced upward to engage or couple the anchor (1200) to the bodyof the elongate instrument or catheter. The location of engagement orcoupling becomes an anchoring point of the flex tube (1206) to theelongate instrument or catheter. In addition, as the anchor wire(1214-2) is operated or tensioned, the cam spring (1232) may becompressed in the activated state. When the anchor wire (1214) isoperated to release the tension on the anchor wire (1214-2), the camspring (1232) pushes the distal anchor puck (1224) toward the distalportion of the anchor (1200). The displacement of the anchor puck (1224)toward the distal portion of the anchor (1200) may cause the cam pins(1228) to travel along the cam pathways (1230) which may cause theanchoring cams (1222) to be displaced downward to disengage or detachthe anchor (1200) from the body of the elongate instrument or catheter.The deployable anchor may be restored to its neutral or undeployedstate. In the neutral state, the flex member (1206) may be displacedalong the length inside a lumen of the elongate instrument or catheter,such as inside the operation tube. The flex member (1206) may bedisplaced by activating a pull wire that may be coupled to the flexmember to pull the flex member (1206) toward the proximal portion of theelongate instrument or by activating push tubes or control members todisplace or push the flex member toward the distal portion of theelongate instrument.

Splayer or Control Unit

FIG. 13A through FIG. 13F illustrate one variation of a control unit orsplayer configured to accommodate and operate multiple flex members,wherein the control unit may include active control components forselective operation or displacement of the flex members. FIG. 13Aillustrates one variation of a control unit (1300) and an elongateinstrument or catheter (1302) coupled to the control unit. The controlunit (1300) includes interface grooves or channels (1304) where the flextubes (1306), pull wires (1314-1), and anchor wires (1314-2) may bedisposed. The control unit (1300) may also include drive pulleys (1326)and drive pins (1328) configured to operate pull wires and anchor wires.The drive pins (1328) may be operated by one or more drive mechanisms inthe instrument driver (not shown). The drive pins (1328) may drive thedrive pulleys (1326) to operate the pull wires (1314-1) and anchor wires(1314-2) to respectively steer or articulate the elongate instrument(1302) as well as drive or displace the flex tubes (1306). FIG. 13Billustrates a close up exposed detail view (View 9-9) of the controlunit (1300) and some of its components and features, such as theinterface grooves or channels (1304) where the flex tubes (1306) aredisposed within the control unit. Furthermore, the control unit (1300)may also include interface slides (1308) which may be configured todrive or displace the flex tubes (1306) as illustrated in detail view(View 10-10) of FIG. 13C. The interface slide (1308) may be operated bya drive mechanism or an interface slide carriage (1310) located in theinstrument driver (1316) of a robotic system, as illustrated in FIG.13D. The interface slide carriage (1310) may be operated by a worm gear,a screw drive, a rail system or any suitable motion control system thatallows the interface slide carriage to be moved or displaced, such thatthe interface slide may be displaced to act on the flex tubes (1306).FIG. 13E illustrates a further close-up detail view of the control unit(1300). This close-up detail view shows that the flex tubes (1306), pullwires (1314-1) and anchor wires (1314-2) are disposed in interfacegrooves or channels (1304-1), while interface grooves or channels(1304-2) may be used by the interface slides (1308) as guide tracks orguide channels for traversing up and down the length of the control unitto displace the flex tubes (1306). FIG. 13F illustrates the underside ofthe control unit (1300). As shown in this figure, the interface slides(1308) may be exposed through the interface grooves or channels(1304-1), such that the interface slides (1308) may be interfaced withthe interface slide carriage (1310) in the instrument driver (1316).

Various Implementations of Flex Members

FIG. 14A through FIG. 14D illustrate various embodiments where flextubes may be secured, placed, or positioned to obtain variousvariability of shape and/or curvature of an elongate instrument by wayof active displacement of the flex tube members as previously described.In addition, the various embodiments, as illustrated in FIG. 14A throughFIG. 14D may also be obtained or configured by way of fixedly couplingthe distal portions of the flex tubes as provided by passivelycontrolled or actively controlled flex tubes installations. FIG. 14Aillustrates an initial state in which one or more flex tubes and theirassociated components of an elongate instrument (1400) may be displacedand/or secured to a first position or location (1400-1), e.g., by adeployable anchor or fixed coupling, along the length of the elongateinstrument in accordance with one embodiment. In this example, theelongate instrument (1400) may have substantially two sections ofvariability (1402-1 and 1402-2) to steer and/or adjust the shape and/orcurvature of the elongate instrument (1400). Section of variability maybe described as a portion of the elongate instrument having particularcharacteristics of axial stiffness, flexibility, and pliability; lateralstiffness, flexibility, and pliability; bending stiffness, flexibility,and pliability, etc. FIG. 148 illustrates another embodiment in whichone of a plurality of flex tubes and their associated components of anelongate instrument (1400) may be displaced and/or secured to a secondposition or location (1400-2) on the elongate instrument (1400), whileone or more different flex tubes may be displaced and/or secured to afirst position or location (1400-1) on the elongate instrument (1400).In this example, the elongate instrument (1400) may have substantiallythree sections of variability (1002-1, 1002-2, and 1002-3) to steerand/or adjust the shape and/or curvature of the elongate instrument(1400). FIG. 14C illustrates another embodiment in which one of aplurality of flex tubes and their associated component of an elongateinstrument (1400) may be displaced and/or secured to a second positionor location (1400-2) on the elongate instrument (1400), while adifferent flex tube may be displaced and/or secured to a third positionor location (1400-3), and one or more of other flex tubes may bedisplaced and/or secured to a first position or location (1400-1) on theelongate instrument (1400). In this example, the elongate instrument mayhave substantially four sections of variability (1402-1, 1402-2, 1402-3,and 1402-4) to steer and/or adjust the shape and/or curvature of theelongate instrument (1400). FIG. 14D illustrates another embodiment inwhich one of a plurality of flex tubes and their associated componentsof an elongate instrument (1400) may be displaced arid/or secured to afourth position or location (1400-4), while another one of a pluralityof flex tubes may be displaced and/or secured to a second position orlocation (1400-2) on elongate instrument (1400), another different flextube may be displaced and/or secured to a third position or location(1400-3), and another flex tubes may be displaced and/or secured to afirst position or location (1400-1) on the elongate instrument (1400).In this example, the elongate instrument may have substantially fivesections of variability (1402-1, 1402-2, 1402-3, 1402-4, and 1402-5) tosteer and/or adjust the shape and/or curvature of the elongateinstrument (1400). As described, the various embodiments illustrated inthis example may be obtained by displacing the flex tubes through theapplication of displaceable control of the flex tubes or by fixedlycoupling the distal portion of the flex tubes at the various locationsalong the length of the elongate instrument in actively controlconfigurations or passively controlled configurations.

FIG. 15A through 115C illustrate a simplified construction of anelongate instrument (1500) with variable shape control and support inaccordance with one embodiment. In this embodiment, the elongateinstrument may be formed into a desired shape in a passive manner. Thatis instead of using pull wires to steer the elongate instrument (1500)into a desired shape or curvature, a separate shape or curvature forminginstrument (1550) may be used to put the elongate instrument (1500) intoa desired shape or curvature. The shape or curvature forming instrument(1550) may be a miniaturized instrument that when it is in its neutralstate, it may be substantially flexible, pliable, and may conform to anyshape or curvatures without significant resistance. As illustrated inFIG. 11A, the shape forming instrument (1550) in its neutral state mayconform to the shape of the elongate instrument (1500). However, when itis activated, it may become erected or stiffened into a preprogrammed orpredetermined shape or curvature, as illustrated in FIG. 15B. Theelongate instrument (1500) in its neutral state conforms to the shape orcurvature of the shape forming instrument (1550). Once the desired shapeor curvature is formed, flex tubes (1506-1 and 1506-2) may be locked inplace to lock the elongate instrument (1500) into the desired shape orcurvature, as illustrated in FIG. 15B. The shape forming instrument(1550) may then be deactivated, so that it may become substantiallyflexible and pliable again. In its deactivated or neutral state, theshape forming instrument (1550) may then be withdrawn from the elongateinstrument (1500), as indicated by the arrow in FIG. 15C. As such, theflexible and steerable elongate instrument (1500) with variable shapecontrol and support may be comprised of a simplified construction withone or more flex tubes and active control to lock the flex tube afterthe elongate instrument (1500) has acquired a desired shape orcurvature. For illustrative purposes, this example describes a method ofusing two flex tubes to lock or maintain an elongate instrument in aparticular desired shape or curvature. As may be appreciated, one ormore flex tubes may be used to lock or maintain an elongate instrumentin a particular desired shape or curvature. In addition, the flex tubesmay be positioned or disposed in various locations, positions, ororientations within the wall or lumens of the elongate instrument toallow the flex tubes to lock or maintain the elongate instrument invarious shapes, curvatures, or orientations.

FIG. 16A through FIG. 16J illustrate various embodiments where flextubes and associated components may be disposed within the wall orlumens of an elongate instrument to provide various variety of steering,articulation, shape, and curvature control to the elongate instrument.The flex tubes may be secured, placed, or positioned in the elongateinstrument to obtain various variety or variability of steering,articulation, shape and/or curvature control of an elongate instrumentby way of active displacement of the flex tube members as previouslydescribed in this disclosure. In addition, the various embodiments, asillustrated in FIG. 16A through FIG. 16J, may also be obtained orconfigured by way of fixedly coupling the distal portions of the flextubes as described in this disclosure by way of passive control oractive control configurations or installations of flex tubes andassociated components. As illustrated in FIG. 16A through 16J, anelongate instrument or catheter (1600) may include an elongate body witha working lumen (1618) and one or more control lumens (1604) wherecontrol elements, such as flex tubes (1606), control wires (1614), andvarious associated components may be disposed. The embodiments asillustrated in FIG. 16A through 16J are for illustrative purposes onlyand not to limit the variety of possible configurations in which theflex tubes and associated components may be implemented to providevarious means to steer and articulate the elongate instrument or tocontrol the shape or curvature of the body of the elongate instrument.With that understanding, FIG. 16A through 16F illustrate a sample ofvariations in which one set of flex tubes (1606) may be configured orimplemented in a set of control lumens (1604) within the body of anelongate instrument (1600). For example, the distal portion of the flextubes (1606) and associated pull wires (1614) may be attached, coupled,or secured to any portion or location on the body of the elongateinstrument (1600) to affect the stiffness and steering, articulation,and bending characteristics of the elongate instrument. For theconfiguration with active control of the flex tubes (1606), theimplementation may also include push tubes or control members (1608) todisplace the proximal portion of the flex tubes. FIG. 16G through FIG.16J illustrate a sample of variations in which a plurality of flex tubes(1606) may be disposed or implemented in a control lumen (1604) of anelongate instrument (1600) to create various stiffness, and steering,articulation, and bending characteristics of the elongate instrument.FIG. 16G and FIG. 16H illustrate examples of a plurality of flex tubes(1606) configured in a substantially parallel configuration within acontrol lumen (1604) affect the stiffness and steering, articulation,and bending characteristics of the elongate instrument. The flex tubes(1606) may be configured or implemented by way of passively controlled,actively controlled, displaceable controlled configuration, orcombination of passively controlled, actively controlled or displaceablecontrolled configuration. FIG. 16I and FIG. 16J illustrate a sample ofvariations in which one of the plurality of flex tubes (e.g., 1606-1) ina control lumen (1604) may be configured in a passively controlledmanner, while one or more other flex tubes (160602) may be configured ina passively controlled manner, actively controlled manner, ordisplaceable controlled manner.

Various Methods of Application

FIG. 17A through FIG. 17F illustrate various methods in which anelongate instrument with passive control, active control, ordisplaceable control may be used to approach and treat a target site ortissue structure in a minimally invasive procedure. In one method asFIG. 17A illustrates, at least a portion, e.g., a first portion ordistal portion, of an elongate instrument may be inserted into a patientpercutaneously through the skin either by way of an incision or orifice,as described in Step 1702. Advance at least a portion, e.g., firstportion or distal portion, of the elongate instrument through a pathwayinside the patient, as described in Step 1704. At least a portion, e.g.,a second portion or proximal portion, of the elongate instrument may bemanipulated to conform, adopt, or match a shape or curvature of thepathway as the elongate instrument is being advanced through thepathway, as described in Step 1706. Steer, or articulate at least aportion, e.g., first portion or distal portion, of the elongateinstrument around other curvatures of the pathway as the elongateinstrument is navigated through the anatomy of the patient, as describedin Step 1708. In another method as FIG. 17B illustrates, at least aportion, e.g., a first portion or distal portion, of an elongateinstrument may be inserted into a patient percutaneously through theskin either by way of an incision or orifice, as described in Step 1712.Advance at least a portion, e.g., first portion or distal portion, ofthe elongate instrument through a pathway inside the patient, asdescribed in Step 1714. At least a portion, e.g., a second portion orproximal portion, of the elongate instrument may be manipulated toconform, adopt, or match a shape or curvature of the pathway as theelongate instrument is being advanced through the pathway, as describedin Step 1716. At least a portion, e.g., first portion or distal portion,of the elongate instrument may be steered or articulated around othercurvatures of the pathway as the elongate instrument is navigatedthrough the anatomy of the patient, as described in Step 1718. Inaddition, articulation forces from steering the one portion, e.g., firstportion or distal portion, of the elongate instrument may be decoupledfrom another portion, e.g., second portion or proximal portion, of theelongate instrument, as described in Step 1719. Furthermore, theconformed, adopted, or matched shape or curvature of the one portion,e.g., second portion or proximal portion, may be maintained by way ofdecoupling the one portion, e.g., first portion or distal portion, ofthe elongate instrument from another portion, e.g., second portion orproximal portion, of the elongate instrument. The act of decoupling thearticulation or steering forces may include preventing a flex memberfrom moving in reaction to the articulation or steering forces andcompressing the flex member to support the articulating or steeringforces. In another method as FIG. 17C illustrates, at least a portion,e.g., a first portion or distal portion, of an elongate instrument maybe inserted into a patient percutaneously through the skin either by wayof an incision or orifice, as described in Step 1722. Advance at least aportion, e.g., first portion or distal portion, of the elongateinstrument through a pathway inside the patient, as described in Step1723. At least a portion, e.g., a second portion or proximal portion, ofthe elongate instrument may be manipulated to conform, adopt, or match ashape or curvature of the pathway as the elongate instrument is beingadvanced through the pathway, as described in Step 1724. At least aportion, e.g., first portion or distal portion, of the elongateinstrument may be steered or articulated around other curvatures of thepathway as the elongate instrument is navigated through the anatomy ofthe patient, as described in Step 1725. In addition, a control membermay be advanced a control unit or splayer against a flex member or flextube, as described in Step 1726, at the proximal portion of the flexmember to hold the flex member at a particular position or orientation.As such, at least a portion, e.g., second portion or proximal portion,of the elongate instrument may be locked in the conformed, adopted ormatched shape or curvature. In another method as FIG. 17D illustrates,an elongate instrument may be inserted into a patient percutaneouslythrough the skin either by way of an incision or orifice, as shown inStep 1732. The elongate instrument may include a first portion, a secondportion, and a third portion, or a distal portion, a mid portion, and aproximal portion. The first portion or distal portion and the secondportion or mid portion of the elongate instrument may be advancedthrough a pathway inside the patient, as described in Step 1734. Atleast a portion, e.g., second portion or mid portion, of the elongateinstrument may be manipulated to conform, adopt, or match a shape orcurvatures of the pathway as the elongate instrument is being advancedthrough the pathway, as described in Step 1736. The second portion ormid portion of the elongate instrument may be locked in place tomaintain the conformed, adopted, or matched shape or curvatures of thepathway while the first portion or distal portion of the elongateinstrument may be manipulated to assume a curvature independent of thesecond portion or mid portion, as described in Step 1738. In anothermethod as FIG. 17E illustrates, an elongate instrument may be insertedinto a patient percutaneously through the skin either by way of anincision or orifice, as shown in Step 1742. The elongate instrument mayinclude a first portion, a second portion, and a third portion, or adistal portion, a mid portion, and a proximal portion. The first portionor distal portion and the second portion or mid portion of the elongateinstrument may be advanced through a pathway inside the patient, asdescribed in Step 1743. At least a portion, e.g., second portion or midportion, of the elongate instrument may be manipulated to conform,adopt, or match a shape or curvatures of the pathway as the elongateinstrument is being advanced through the pathway, as described in Step1744. Controlling the displacement of a flex member within the elongateinstrument, wherein the flex member may be configured to assist withsteering or articulation of the elongate instrument, as described inStep 1746. Steering a first portion or a second portion of the elongateinstrument around curvatures of the pathway inside the patient, asdescribed in Step 1748. In another method as FIG. 17F illustrates, anelongate instrument may be inserted into a patient percutaneouslythrough the skin either by way of an incision or orifice, as shown inStep 1752. The elongate instrument may include a first portion, a secondportion, and a third portion, or a distal portion, a mid portion, and aproximal portion. The first portion or distal portion and the secondportion or mid portion of the elongate instrument may be advancedthrough a pathway inside the patient, as described in Step 1753. Atleast a portion, e.g., second portion or mid portion, of the elongateinstrument may be manipulated to conform, adopt, or match a shape orcurvatures of the pathway as the elongate instrument is being advancedthrough the pathway, as described in Step 1754. Controlling thedisplacement of a flex member along a length of the elongate instrument,wherein the flex member may be disposed within the elongate instrumentand the flex member may be configured to assist with steering orarticulation of the elongate instrument, as described in Step 1755. Thestiffness of at least a portion, e.g., first portion or distal portion,of the elongate instrument may be altered by the displacement of theflex member, as described in Step 1756. In addition, the radius ofcurvature for a least a portion of the elongate instrument may bechanged by the displacement of the flex member, as described in Step1757. After altering the stiffness and/or radius of curvature of atleast a portion of the elongate instrument, steer a portion, e.g., firstportion or second portion, of the elongate instrument around curvaturesof the pathway inside the patient, as described in Step 1758.

Multiple embodiments and variations of the various aspects of theinvention have been disclosed and described herein. Many combinationsand permutations of the disclosed system may be useful in minimallyinvasive medical intervention and diagnostic procedures, and the systemmay be configured to support various flexible robotic instruments. Oneof ordinary skill in the art having the benefit of this disclosure wouldappreciate that the foregoing illustrated and described embodiments ofthe invention may be modified or altered, and it should be understoodthat the invention generally, as well as the specific embodimentsdescribed herein, are not limited to the particular forms or methodsdisclosed, but also cover all modifications, equivalents andalternatives. Further, the various features and aspects of theillustrated embodiments may be incorporated into other embodiments, evenif not so described herein, as will be apparent to those ordinaryskilled in the art having the benefit of this disclosure. Althoughparticular embodiments of the present invention have been shown anddescribed, it should be understood that the above discussion is notintended to limit the present invention to these embodiments. It will beobvious to those skilled in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe present invention. Thus, the present invention is intended to coveralternatives, modifications, and equivalents that may fall within thespirit and scope of the present invention as defined by the claims.

What is claimed is:
 1. A steerable elongate instrument, comprising: anelongate body, comprising: a proximal portion; a distal portion; a firstlumen extending through the proximal portion and the distal portion; andmultiple secondary lumens extending through the proximal portion and thedistal portion; multiple flex tubes disposed within the secondary lumenswithin the proximal portion of the elongate body, wherein a proximalportion of each flex tube is slideable into and out of the elongate bodyat a proximal end of the elongate body, wherein a distal end of eachflex tube is fixedly coupled to a distal end of the proximal portion ofthe elongate body, and wherein, when the elongate body is placed in abend such that a first side of the elongate body contracts and a secondside of the elongate body stretches, one of the flex tubes located inthe first side slides at least partially out of the secondary lumen inwhich it is disposed, and another of the flex tubes located in thesecond side slides at least partially into the secondary lumen in whichit is disposed; multiple pull wires, wherein each of the flex tubes hasa different one of the pull wires disposed therein; and a control unitpositioned proximal to the elongate body, wherein a distal portion ofeach of the pull wires is coupled to the distal portion of the elongatebody, and wherein a proximal portion of each of the pull wires isoperatively coupled to the control unit.
 2. The elongate instrument ofclaim 1, wherein the distal portion of each of the pull wires is coupledto the elongate body via a control ring fixedly coupled to the elongatebody.
 3. The elongate instrument of claim 1, further comprising multipleliners, wherein each of the liners is disposed within each of thesecondary lumens between the secondary lumen and the flex tube andcomprises a slidable surface for the flex tubes to slide within thesecondary lumens.
 4. The elongate instrument of claim 1, configured suchthat a tension applied to the pull wires via the control unit results inarticulation of the distal portion of the elongate instrument.
 5. Theelongate instrument of claim 1, wherein each of the flex tubes is a coiltube.
 6. The elongate instrument of claim 1, wherein each of the flextubes is a ring tube.
 7. The elongate instrument of claim 1, whereineach of the flex tubes is a spirally cut tube.
 8. The elongateinstrument of claim 1, wherein the flex tubes are configured to supportarticulation forces that steer the distal portion of the elongate bodywhile decoupling the articulation forces from the proximal portion ofthe elongate body.
 9. The elongate instrument of claim 1, wherein theflex tubes are configured to support articulation forces that steer thedistal portion of the elongate body such that the proximal portion ofthe elongate body remains flexible while the articulation forces areapplied.
 10. The elongate instrument of claim 1, wherein a proximal endof each of the flex tubes is fixedly coupled to the control unit orother structural element such that outward sliding of one of the flextubes from the elongate body forms a buffer loop that maintains aconstant path length for the respective pull wire for accuratearticulation as the elongate instrument is steered through a patient'sanatomy.
 11. The elongate instrument of claim 1, wherein the controlunit is a splayer.
 12. A steerable elongate instrument, comprising: anelongate body, comprising: a proximal portion; a distal portion; a firstlumen extending through the proximal portion and the distal portion; anda secondary lumen extending through the proximal portion and the distalportion; a flex tube disposed within the secondary lumen within theproximal portion of the elongate body, wherein a proximal portion of theflex tube is slideable into and out of the elongate body at a proximalend of the elongate body, wherein a distal end of the flex tube isfixedly coupled to a distal end of the proximal portion of the elongatebody, and wherein, when the elongate body is placed in a bend orientedsuch that the flex tube is positioned in a contracted side of theelongate body, the flex tube slides at least partially out of thesecondary lumen, and when the bend is oriented such that the flex tubeis positioned in a stretched side of the elongate body, the flex tubeslides at least partially into the secondary lumen; a pull wire disposedwithin the flex tube; and a control unit positioned proximal to theelongate body, wherein a distal portion of the pull wire is coupled tothe distal portion of the elongate body, and a proximal portion of thepull wire is operatively coupled to the control unit.
 13. The elongateinstrument of claim 12, wherein the distal portion of the pull wire iscoupled to the elongate body via a control ring fixedly coupled to theelongate body.
 14. The elongate instrument of claim 12, furthercomprising a liner disposed within the secondary lumen between thesecondary lumen and the flex tube and comprising a slidable surface forthe flex tube to slide within the secondary lumen.
 15. The elongateinstrument of claim 12, configured such that a tension applied to thepull wire via the control unit results in articulation of the distalportion of the elongate instrument.
 16. The elongate instrument of claim12, wherein the flex tube is configured to support an articulation forcethat steers the distal portion of the elongate body while decoupling thearticulation force from the proximal portion of the elongate body. 17.The elongate instrument of claim 16, wherein the flex tube is configuredto prevent compression of the proximal portion of the elongate body fromthe articulation forces while maintaining flexibility of the distalportion of the elongate body.
 18. The elongate instrument of claim 12,wherein a proximal end of the flex tube is fixedly coupled to thecontrol unit or other structural element such that outward sliding ofthe flex tube from the elongate body forms a buffer loop that maintainsa constant path length for the pull wire for accurate articulation asthe elongate instrument is steered through a patient's anatomy.
 19. Theelongate instrument of claim 12, wherein the control unit is a splayer.20. The elongate instrument of claim 12, wherein the flex tube isselected from the group consisting of a coil tube, a ring tube, and aspirally cut tube.